As pancreatic ductal adenocarcinoma (PDAC) is extremely malignant and refractory, therapeutic options for this cancer are anticipated worldwide. We isolated vasohihibin-2 (VASH2) and observed its overexpression in various types of cancer. We then noticed that upregulated expression of VASH2 in patients with PDAC resulted in a conspicuous reduction in the postoperative survival period and further revealed that the abrogation of Vash2 expression in pancreatic cancer cells inhibited its growth and metastasis and augmented tumor infiltration of CD8+ cells in the mouse model. We developed VASH2-targeting therapies, 2',4'-BNA-based antisense oligonucleotide targeting VASH2 (VASH2-ASO) as a nucleotide-based therapy, and VASH2-peptide vaccine as an antibody-based therapy. We also showed that the VASH2-peptide vaccine inhibited PDAC metastasis in an orthotopic mouse model. Here, we expanded our analysis of the efficacy of VASH2-targeting therapies for PDAC. VASH2-ASO treatment inhibited the growth of primary tumors by reducing tumor angiogenesis, normalizing tumor vessels, preventing ascites accumulation and distant metastasis to the liver and lungs, and augmenting the infiltration of CD8+ cells in metastatic tumors. VASH2-peptide vaccine did not affect the infiltration of CD8+ cells into tumors. The present study revealed that VASH2-targeting therapies are promising options for the treatment of PDAC. VASH2-ASO therapy can be administered at any stage of PDAC. Because of the increase of CD8+ cell infiltration, the combination therapy with immune checkpoint inhibitors may be an attractive option. The VASH2-peptide vaccine therapy may be useful for preventing metastasis and/or recurrence after successful initial treatment.
Keywords: modified antisense oligonucleotide; molecular targeting therapy; pancreatic ductal adenocarcinoma; peptide vaccine; vasohibin-2.